Instability and other maladies of human joints, such as arthrosis or fracture, can be sufficiently acute that prosthetic replacement of compromised joint features may be indicated. For example, in shoulder reconstruction, the humeral head may be replaced by first resecting the humeral head from the humerus and then installing a humeral prosthetic at the resection.
Various prostheses have been designed to mimic the portion of the joint or joint region being replaced. A shoulder prostheses, for example, includes a stem to be anchored in the humeral canal and a hemispherical head to be positioned within the glenoid cavity of the scapula. The more-recently devised modular shoulder prostheses generally are modular systems that allow flexibility with respect to either the tilt angle or the radial offset between the head and stem.